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Delayed in situ crosslinking of acrylamide polymers for oil recovery applications in high-temperature formations

US 4,844,168 A · Assignee: Marathon Oil Company · Inventors: Sydansk; Robert D.

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Listed from its USPTO record in Patent Yard's full-term archive. Its claims, description and drawings are in the USPTO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed February 9, 1988 and granted July 4, 1989. A patent filed before June 8, 1995 lasts 17 years from grant or 20 from filing, whichever is longer, so its term ended February 9, 2008.
  • Any extension is capped at five years, so it can't still be in force.
  • We haven't checked its US family, and a later related patent could still be in force. We check US rights only.
FiledFebruary 9, 1988
GrantedJuly 4, 1989
Term endedFebruary 9, 2008
Application number07/153860
Classification (CPC)C09K8/512
Length9 pages

Timeline

Timeline From USPTO dates

1989199119931995199719992001200320052007Application filedFeb 9, 1988Patent grantedJuly 4, 1989Term endedFeb 9, 2008

Sources & verification

Official USPTO records

Full published documentText and every drawing sheet as a PDF.USPTOFile historyStatus, office actions, notices, fee records and petitions.USPTO Patent CenterPatent Public Search recordSearchable full text and bibliographic data.USPTO

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